This invention relates generally to beverage dispensing system, and more particularly to a system with programmable dispensing buttons for dispensing a programmed amount of product.
Beverage dispensers, such as those used in the restaurant industry, are well-known in the art. Some such dispensers, such as the one disclosed in U.S. Pat. No. 5,731,981 to Simard, include a keypad at a dispensing end that dispense a metered amount of product at the press of a button. Each of the buttons of the keypad is preprogrammed to activate a sequence whereby a selected type of mixed drink in a desired quantity is dispensed. As with most other dispensing machines of this type, the Simard device uses flow meters to regulate the amount of product dispensed.
One noted drawback to Simard-type systems using flow meters is their inability to accurately dispense desired quantities of products having a variety of different viscosities. It is generally understood that the higher the viscosity of the product dispensed, the higher the pressure the pump must exert to drive the product from the storage container to the dispensing end of the machine and/or the longer the flow valve must be kept open. The viscosity of certain types of products, such as juice concentrate, is further complicated by such environmental factors as ambient temperature, humidity and altitude. Using Simard-type systems to dispense a desired amount of such product with the single press of a button on the dispensing end of the machine would result in an inaccurate dispensed amount.
Programming of dispenser buttons is also known in the art. For example, U.S. Pat. No. 5,492,250 to Sardynski discloses a beverage dispenser having control buttons. A user programs the buttons in a learning mode by filling a container to a specific level; a button is then programmed to dispense that level of fluid. However, the xe2x80x9clearning modexe2x80x9d in conventional dispensers is somewhat rudimentary, in that a user must dispense a chosen amount of product in one aliquot. Such coarse button calibration is undesirable where a concentrated product is intended to be mixed with another fluid, e.g., fruit juice concentrate and water.
Accordingly, the need remains for a system that allows greater programmability of the amount of product dispensed, as well as flexibility according to the flow characteristics of the various products.
An important element of the new dispenser design is the programmability of the dispenser buttons. When a switch on the dispenser head is activated, the device is placed in learning mode. Pressing one of the dispenser buttons starts a timer on the circuit board. Concurrently, a signal is sent from the controller portion of the circuit board to a designated solenoid valve on a valve manifold assembly mounted within the dispenser casing. The signal retracts the solenoid and compressed air travels through the valve to a pump for as long as the button is depressed and the signal activated, thus driving one of the liquids to the dispenser head.
A user can press and release the button several times until a desired amount of liquid is dispensed. An accumulator on the circuit board totals up the amount of time the button is depressed and programs that accumulated time amount into a memory subsystem on the circuit board. When the button is depressed again and the machine is in normal (non-learning) mode, the solenoid signal is active for the amount of time stored in memory for that particular button. In this way, the machine can be easily calibrated and adjusted for dispensing a variety of different liquids in a variety of different controllable amounts under a variety of conditions.
Another important element of the operation of the device is the fact that the pumps do not have an automatic shutoff system but are only active for as long as compressed air is delivered to the pump. Tests have shown such an arrangement to limit stalling.
Still another important feature is the use of a check valve immediately adjacent the dispensing head to control drippage.